The suit takes aim at three services: Morpheus, Grokster and Kazaa. Kazaa's distributor, Sharman Networks, contended that it could not be sued in the US because it is incorporated in the South Pacific island nation of Vanuatu and has no substantial ties here. It did not take part in Monday's hearing but remains a defendant in the lawsuit.
As expected, no ruling was issued after the two-hour hearing, in which attorneys for the music and motion picture industries squared off against lawyers for file-swapping systems Morpheus and Grokster. The judge is expected to issue a ruling in the coming weeks that will determine whether or not the case goes to trial.
The entertainment industries accuse the peer-to-peer operators of assisting copyright infringement on a massive scale and have asked the court for a summary judgment that would bring their file-trading services to a close.
If the judgment were granted it would spell a resounding victory for the copyright holders, which have battled the peer-to-peer trading of their works since the advent of Napster.
The peer-to-peer operators, meanwhile, are seeking a summary judgment of their own, asking that the case be thrown out of court.
Monday's hearing was intended to help the judge decide whether to grant either sides' motion or allow the case to go to trial, an option some observers have said is more likely.
The judge's questions centred on such matters as how much control the file-swapping services have over the content traded by their members, and to what extent they are responsible for any copyright infringement that may occur.
If the summary motions are refused, the case will go to trial. Napster and fellow file swapper Aimster (which now operates under the name Madster) both were hit with preliminary injunctions to block copyright-protected works from being traded. Napster closed down in bankruptcy last year and Madster is still fighting the injunction.
The "new generation" peer-to-peer companies argue they are significantly different from the file-swapping networks of old in that they do not have central servers and, therefore, cannot easily be shut down. They also contend that their software can be used for a variety of "non-infringing" uses, such as allowing people to share their own digital photographs and over the Internet, and say they are software distributors with no control over what gets traded using their applications.
However, lawyers for the recording and motion picture industries have argued that the defendants' file-swapping systems were designed to "emulate Napster, and then to surpass it", adding that they achieved that goal "beyond their wildest dreams".